As each successive generation of semi-conductor devices, such as microprocessor chips, becomes smaller than the preceding generation of chips, they become increasingly intricate. To accommodate the ever expanding number of chip components, typically transistors, on the ever shrinking chip space, the transistors have become submicroscopic in size and of very high densities. The high density means greater heat generated in a smaller volume with resulting temperature increases. The transistors and other semiconductor components are vulnerable to the heat they themselves produce.
Whereas the heat generated by older generation chips could adequately be dissipated through convection into the static air mass surrounding the chip, or a circulating air mass, their progeny generate significantly more heat, and the heat dissipation requirement is more problematic. Currently, state of the art chips dissipate as much as 30 watts. The next generation of chips is expected to be at power levels which cannot be adequately cooled by conventional structures, such as extruded aluminum heat sinks or fans.
Designers of work stations and PC's are extremely reluctant to provide active cooling means, such as the forced circulation of a cold fluid, because of the cost, reliability and noise associated with them. With respect to compact lap-top computers, the adverse impact on battery life that forced cooling would impose is an additional limitation.
An inexpensive, quiet, reliable and energy efficient alternative to the motor driven fan is a heat sink, which draws heat away from the chip by conduction and provides a supplemental heat convecting surface. Traditional heat sinks such as extruded aluminum finned radiators, however, convect to the internal environment where there is already heated air. Also limited dissipation surface area is provided. It would therefore be advantageous to retain the benefits of a heat sink, while increasing convective surface area, yet decreasing space requirements in the vicinity of a heat producing device such as a chip. It would also be advantageous to place the dissipation surface area at a remote location from the chip.